Question

A triangle has side lengths of 18 cm, 80 cm, and 81 cm. Classify it as acute, obtuse, or right

Answer 1

An acute triangle has all internal angles less than 90 degrees.
An obtuse triangle has one internal angle greater than 90 degrees.
A right triangle has one internal angle equal to exactly 90 degrees.

Using Soh Cah Toa, can you work out what this triangle would be?

Answer 2

we can assume that c = 81 in pyth theorem since it is the longest line

a^2 + b^2 > c^2 obtuse angle
a^2 + b^2 = c^2 right angle
a^2 + b^2 < c^2 acute

use a = 18 and b = 80